Genre recognition on device

I want to be able to use the Pocketbook Era's sort by Genre function for books.

After researching, I stumbled across this previous post discussing it (see below) and followed the instructions for setting up Genres in Calibre.

https://www.mobileread.com/forums/sh...ighlight=genre

However, step 3 says:
In calibre adding a metadata plugboard with:
Format: epub,
Device: Pocketbook740 (for the Inkpad 3),
Source template: {#genre} - assuming you called the custom column lookup name from 1. above #genre,
Destination field: tags

Would someone please be able to provide additional details on this?
I do not understand what a metadata plugboard is or how to complete this final task.

Thank you for reading my post and for any help you can provide.